Hey, welcome to Stuff to Blow Your Mind. This is Robert Lamb. I've you been listening this week. You know the deal. We're on vacation, we're re airing. You've got femail. This is going to be part two of three and it originally published five twenty five. Let's happen.
Welcome to Stuff to Blow Your Mind, production of iHeartRadio.
Hey, welcome to Stuff to Blow your Mind. My name is Robert Lamb.
And I'm Joe McCormick, and we're back with part two in our series on urine based communication in animals. In Part one, we introduced the idea that while humans have an almost infinitely expanding arsenal of tools and skills and tricks for sharing information with one another, one medium that we don't use, or at least don't use very much, but which is used throughout the animal kingdom is urine.
So in part one we also talked about a story that the story that initially got me interested in covering this on the show, which was a recent paper documenting a behavior in Amazon river dolphins called aerial urination, which goes like this. One male dolphin floats upside down and urinates in a stream up in the air over the water, and then usually another male dolphin seeks out the stream, swims over and puts its face right into the pea fountain.
It's not yet known why the dolphins do this, but the researchers who wrote the paper propose that it is a form of communication. It's information sharing between male dolphins to sort of give a fact sheet about the originator of the urine stream, kind of have a look at my medical chart. Here you can sense my urine with the whiskers on your snout and get a sense of me.
And of course we talked also about how urine can convey lots of different kinds of information about physical health, social dominance and things like that, and those pieces of information are useful for male dolphins to share with one another because it helps them make decisions about whether to challenge each other for access to food resources or mates. We also talked more generally about what urine is and is not, and what kind of information it contains to
a fluent reader. We also went on some other interesting tangents, for example, about why so many animals actually have voluntary control over urination in the first place, why can they actually decide when they want to release the urine. We talked about how urination actually can be thought of as a kind of social behavior in humans, and a bunch of other things, and we're back today to talk more about pe based communication.
Yeah. Yeah, Like, in general, there's just a lot of information in urine, but as humans we cannot pick up on most of it via our own senses. We can turn to technology. May come back to some of that later on, but basically in this episode, we're going to be talking about the various ways that some animals can read the urine of others and perhaps communicate through their own urine.
Yes, now, I'm sure the subject of trading information through urine has had all of the dog owners in the audience like desperately raising their hands and saying ooh ooh, I know one. And yes, we briefly touched on this last time. But domestic dogs are a great example. They are well known for being prolific scent markers and for being very concerned with gathering information from the markings left
by other dogs. And while urine is actually not the only method domestic dogs use in scent marking, it is you can probably think of it as the primary one. Now some dog lovers out there might be thinking, huh that there are other methods beyond urine. Yes, there actually are. I don't know if I would have said this before I started research for this episode, but there are other
ways that dogs leave scent marks. One thing, of course, is the dreaded anal glands, which produce a pungent, foul smelling fluid that gets expressed and deposited naturally in small quantities when a dog defecates, but it can be expressed and rubbed off in other situations as well, and these secretions contain identifying information about the dog. Another interesting example is that dogs have scent producing apocrine glands in their paws.
Apocrine glands are glands that produce a kind of oily sweat. Humans have them in parts of their bodies too, like you've got them in your armpits and stuff. But dogs have apocrine glands in their paws and the regions in between their digits, meaning that a dog can leave a scent mark by scratching at the ground or sometimes even just by walking on the footpaths leave a little scent trail through time.
Many are the stinks of the dog, beautiful.
Stinks, but yes, scent marking by urine is the most overt and visible, certainly of the dog's marking behaviors. You see it most frequently in male dogs who have not been neutered, but it is also done by female dogs and neutered males.
Here's a potentially dumb dog question. Never had an indoor dog and never had a dog as an adult, How does one keep an indoor dog or an indoor outdoor dog from marking territory within the household.
Well, that's a good question.
Rob.
It varies from dog to dogs. Some dogs it's just going to be a struggle keeping them from doing it. Some dogs that have been living inside for years will still continue to mark the chair, you know, like here I am, I'm marking the chair once again. But no, most of the time, a dog will respond to training. You know, I'm not a dog behavior expert, know what all the training the best training methods are these days. But yeah, dogs will respond to training that to get them to save it for outside.
Okay, gotcha.
But it often does mean that when you know, especially with some dogs, you take them outside and maybe you want to get the get their business done quickly. Maybe you're on a timeline, you've got to do something else. But it's kind of hard to get them to like pee all the pee that they need to pee at once. Instead, they want to go all around the neighborhood and leave little marks here and there and just dole it out a little bit at a time.
Because coming back to what we've been talking about, the dog is not just going out to relieve itself and then come back. It has messages to leave messages to and to interpret and so forth.
Yes, it's it's business time when it's time for the walk. Yeah, time to time to check and send some emails. And it is very worth noting, I think we said this last time, but worth really stressing that we do not know all of the different kinds of information that are conveyed when a dog leaves a urine mark and another dog smells it. But we do know some things. There are reasons to suspect a lot of different kinds of information might be shared, and I can go through some
examples here. One thing is a dog's unique identity. There is evidence that dogs can identify other individual dogs by urine smell useful for knowing who's around right, So the same way that a human might be able to recognize another person by seeing a picture of them, like, oh, that's you know, that's Harry, I know Harry. A dog can uniquely identify another individual dog by the smell of their urine. Another thing, similar to what we talked about
in the dolphin example is health information. Urine probably reveals a lot about how healthy the dog is, whether they have diseases or parasites, what kind of shape or fitness they're in, probably age. Urine certainly reveals sex and reproductive information. It reveals the sex of the dog, but also hormonal content can reveal how receptive the dog currently will be to mating. Urine can reveal dominance within the dog's social
group that could be revealed through marking behavior. And then it gets in There are even like weirder, more interesting things. One is that dogs may possibly even communicate momentary emotional information through urine. This is less certain than some of the other ones. Some of the other ones I was just naming are pretty well known. This is less certain,
but it seems likely. Like for example, it has been found that dogs can tell the difference between the smell of a stressed out humans urine versus human urine at baseline, they actually can smell your fear. They can smell your stress and anxiety at least in your pee. Now do they actively seek this information about other dogs? And if so, does this information change their behavior? Like how do they react to getting that information? The answers to these questions
are not known for sure. But regarding that second question, I did find an interesting study by par Cortes at All published in the journal Scientific Reports in twenty twenty four called the odor of an unfamiliar, stressed or relaxed person affects Dog's responses to a cognitive bias test, and this study found that dogs would preferentially avoid food bowls in locations that had been previously associated with the smell of urine from a stressed out human, suggesting that the
smell of stress, at least human stress, could play a role in cognition and learning for dogs.
That is fascinating.
Again, we don't know if dogs use this information about other dogs, though it seems quite plausible. You can imagine maybe dogs I don't know, the like if there is an area where there are a lot of scent markings that have high stress. I don't know, that could signal to the dog, They're like, uh, oh, there's something to be concerned about here. I need to you know, be more on guard or something.
Yeah. Yeah, I mean, as we've discussed before, dogs very social animals, and via domestication, we are their social group, we are their pack, and therefore, you know, the importance of this information, like to the wolf concerning other wolves, is also potentially important concerning the human members of their domesticated pack. Yeah.
I wonder if for a dog, like going down the sidewalk smelling a bunch of urine marks from other dogs that all have like stress in them, is like the human equivalent of doom scrolling.
It could be yeah, going to a community meeting where people get to volunteer their opinions, hair, their fears.
Yeah, exactly. But it really is interesting to imagine, Like I don't know what kinds of complexity are there in like if momentary kind of emotional states even can be communicated across time in these chemical signatures. This is probably overinterpreting.
I don't know when analogies like this are warranted or not, but I'm imagining a kind of p based literature almost, you know, the same way that poetry contains emotions and so forth, Like, what is the kind of richness of the experience that a dog has when smelling all these different health states and sexual information and threat information and emotional information all at the same time.
Yeah, I mean, their sense of smell is just so ratcheted up above anything that we can truly even relate to, you know, outside of our human use of comparisons and metaphors and so forth, that I mean, I don't know that it's it's really out of bounds to say something like that. It seems like that's the best we can get at in trying to understand like how a dog experiences the world.
I think we probably only have the barest kind of idea of what really is happening in this information exchange.
Yeah. I keep coming back to that Terry Pratchett comment about a werewolf character being essentially able to smell through time to like know the interpersonal history of a space going back like a month. And that's the kind of thing that like, as humans highly visual that we are, like, we don't really have something like that unless you're dealing with some like very obvious physical signs of passage, such
as you know, muddy bootprints and so forth. Yeah, but the smell left by something, I mean, at least to us, that's far more subtle to the dogs, I guess, far more overt, but in a way that it's really hard for us to compare, you know, like, what is is there anything like that in our own actual sensory environment that compares to it? I guess the closest you could come would be something that is electronic or literature based.
Or actually I think maybe the more core equivalent would be language that, like with language, humans create for ourselves. It's like our core technology. It's the thing we use to create this like rich layer on top of reality where we can recall past and project future and imagine counterfactuals, and it's all there in constructs that we build out of words. Yeah, coming back to dogs in the female, we also know that dogs use urine based scent marking
in expressions of territoriality. Though this is something that I think we have to be a little cautious about because it seems to me this is something that easily gets oversimplified. Like a common thing you'll hear people say, is that when a dog does a p mark out there somewhere they're like marking the boundary of the territory, like here's my property line, no crossing, no trespassing on my turf.
From what I can tell the current research actually paints, it's a more complicated picture of how urine marking and territoriality interact. However, it does seem that at least one major aspect of urine marking is related to territoriality and dominance. It is to both signal your own ability as a competitor and possible threat to other competing dogs in the area, especially to other dogs of the same sex as you, and then also to gain information about possible rivals and
to understand how much of a threat they represent. I found one study from twenty twelve that looked into this especially. It was looking at the territorial and dominance threat aspects of urine scent marking, and this was in free ranging
domestic dogs. The study was by Cafaso, Natali and Valseki in the journal Ethology, and it was called Scent marking behavior in a pack of free ranging domestic Dogs in their abstract to the author's right quote, we found evidence that markings are used by dogs to form a property line and to threaten rivals. During agonistic conflicts, both males and females utilized scent marking to assert dominance and probably
to relocate food or maintain possession over it. Raised leg urination and ground scratching probably play a role in olfactory and visual communication in both males and females. Urinations released by females, especially through flexed leg posture, may also convey information about their reproductive state. All right, so there are a range of different things there, but one of the
main things they mention is about territoriality. However, this does not mean that a dog only places a urine mark on ground that they expect will never be crossed by an unfamiliar dog. It's not so much a balance line that cannot be violated. Instead, it's more kind of a an announcing of your presence within an occupied space.
Uh.
And so like we're trying, we're trading information about one another. And uh, you you know, with this information about me, you might want to go somewhere else or you might not.
Yes, yeah, saying this is who I am, this is what I'm all about. And we touched that. We touched on this in the last episode and it's gonna continue to be important. We need to remind ourselves. One of the important things about communication between especially competing males UH, but also competing females, is that the more information that is exchanged and that is visible, the less actual physical
violence is needed to to to solve these various interactions. Yes, and of course that benefits all of the organisms involved, because every fight UH brings with it a cost, a potential injury, and with every potential injury, you know, possibility to be weakened, to become sick, and so forth. If any of that can be avoided through communication, all the better.
Exactly, honest information benefits both parties. However, that's honest information. It's different to ask the question could information represented through urine possibly be dishonest? And that brings me to a paper that I came across that I wanted to talk
about here can urine based communication involve lying? So there was a study published in the year twenty eighteen in the Journal of Zoology by McGuire, Olsen Bemis, and Oraantes called urine marking in male domestic dogs Honest or Dishonest. The lead author here, Betty maguire, is a behavioral ecologist at Cornell University. So the study got me thinking about
an interesting question. Of course, when we're talking about human communication, there are actually two completely different modes of information shearing, which have different goals and rely on different skills. You've got normal, truthful communication, and then you've got deceptive communication aka lying. Both modes can be useful in life. Both can be useful for gaining advantage and forgetting what we want,
but they rely on different mechanisms and skill sets. For example, to communicate truthfully, if you want to communicate the truth successfully, you need to know what the truth is, so like your various powers of perception and logical reasoning are implicated in truthful communication, also like your ability to translate that knowledge into the medium of communication you're using with minimal
loss of informational fidelity. On the other hand, to lie successfully, you need to have other skills, like a good ability to simulate the minds of other people to know what kinds of false beliefs would get them to act the way you want and what kinds of lies would be believable to them. And of course, lying also comes with major risks If you get caught lying at the very least people will stop believing you, they'll stop trusting and cooperating with you, or worse, they may actively punish you.
Humans can switch easily between truthful and deceptive communication because we communicate with language, which is able to represent an infinite array of both factual and counterfactual statements. But you might think, you know, urine is not like that, urine is honest. We sort of put it this way last time. Like with language, you can have near total control over what you say. With urine, it seems usually you cannot control what you say, only where, how, when, and whether
you're going to say something at all. If you say something with urine, usually it's going to be honest or least we would assume.
Yeah, that's the human experience with it, right. If you are worried about your urine saying something you don't want to say, in certain specific circumstances, you may get someone else's urine to stand in for your own, with perhaps limited success. But but yeah, there's this idea that like the urine is just a readout. It's just straight up information.
It's not something that can be manipulated outside of manipulating like the system that produces said urine which again we still only have like a limited ability to do that to ourselves.
You know.
It's like we can change what we eat, what we consume, but the urine is going to tell us who we are.
Right, you can maybe think of lying with human urine. I don't even know if this is possible, but maybe you could take some kind of pill that like changes your urine profile to something else.
Or if you're like I don't want this drug to show up in my urine, I'm going to get them. I'm going to stop taking that drug. Yeah, boom, I tricked them. Well you didn't really trick them. You just change the truth will read out of your system in that scenario.
Well this is good because actually I think there will be a question when I'm done talking about the study about whether this should count as deception or lying or not. But anyway, yes, So the researchers here in this paper observed an interesting pattern that might be a counterexample to the assumed honesty of urine, which is dogs potentially being deceptive with their urine scent markings. So how would a dog send a deceptive scam message over the seemingly honest
medium of pemil let's go to the paper. So the authors begin by noting that a bunch of different mammals leave scent marks, and lots of the mammals that do tend to elevate them, meaning they place the mark not on the ground, but up higher, often on some kind of vertical surface. Dog walkers are probably going to be
familiar with this. A dog, they will usually like to pee on landmarks, the telephone pole, the fire hydrant, the mailbox posts, the tree trunk, the flower, the clump of tall grass, or some times, let's be real, the furniture. Why is this? Why do they like to pee on the raised thing and not just wherever? Why not just on the ground. The authors say that this could be because elevated marks are easier for other dogs to detect via both site and smell. So they cite a bunch
of different research here. One thing is researched by Alberts from ninety two, about which they write, quote the ground physically restricts diffusion, meaning the spreading out of the urine physically restricts diffusion. So both size of mark and likelihood of detection by olfaction are increased when the scent marks
are elevated. So when you pee on an elevated vertical object on the fire hydrant instead of just on the ground, it tends to increase the size of the splatter area and thus how easy it is to both see and smell the mark in the future. The other interesting things worth noting the ground has more other smells already within it, so peeing on an elevated object helps isolate the message of your pemail in order to increase the signal to
noise ratio. Kind of like how if you're going to write a message on something with a magic marker, you would look for a blank, relatively blank space to write on, not something that already had tons of different markings and color variations on it. Also, two more things. Elevated marks are closer to the nose height of other dogs. That's
just courtesy, you know. But then finally, elevated marks are visually conspicuous and can be seen at great distance, So you kind of have a biological you can imagine like a communication culture among dogs where they can be wandering around around in an area wondering if there are any good pe mail messages to read, and they see a stump or a fire hydrant at a distance and they know, ah, that's a good place to check for messages. I'll go sniff and see. So these are previously accepted reasons why
dog might might try to elevate their urine mark. It helps get the message out there, It makes it easier to find, and makes it easier to decipher upon being found. However, increased detectability should benefit all animals that scent mark. And something that's kind of interesting that the author's note is that in lots of mammal species, on average, males elevate their scent markings much more often than females do. The motivations for scint marking are somewhat variable according to sex.
Like we were talking about earlier, dogs are more likely to view dogs of the same sex as competitors and thus as threats. Male dogs especially will more often react to other males as competitors and threats, and this is given as a possible reason for why male dogs are more likely to use the raised leg posture when elevating
their scent marks. They might be doing this so that they can leave the mark higher on the tree trunk and thus appear to a dog that comes along later to have been bigger and thus a more formidable competitor. You know, So the other dog comes along and smells it, they can't the dog's not here anymore. They can't see them and evaluate them. So they're getting some information just through the smell of the urine about health and maybe even emotions and sex and dominant status and stuff like that.
But they can't see the dog, and they might smell a higher up urine mark and think, oh, don't want to mess around with this guy. His urine is above the chain on the fire hydrant. That's a big boy.
Yeah. He definitely smells anxious but also enormous.
Yeah, so interesting possibility. Maybe that contributes to the desire to place the urine mark higher. And this brings us to the experimental finding by Maguire at all. So in this experiment, the author is like walked around with a bunch of adult male shelter dogs and just took measurements about their urine marks. They were like apparently filming them and trying to measure everything, and they found something funny
and interesting. The smaller the dog, the higher it would lift its leg to p The angles of leg lifts observed in this study varied between eighty five degrees and one hundred and forty seven degrees. That's a stretch that's really good. Eighty five degrees is not even a right angle, though. But on average, the smaller the dog, the greater the angle. The little dogs would lift their legs the highest. And so there are a number of different things that could
explain this, some more mundane and some more interesting. In terms of the more mundane possibilities, it's very important to consider these as well. One could just be anatomy. I was reading a write up of this research in Science magazine. In this article quoted another researcher in the field, an ethologist at the University of Pennsylvania School of Veterinary Medicine named James Sirple, who said, you know, there are a couple of possibilities apart from the main interpretation of the authors.
One of those is anatomy. Maybe small dogs are more flexible or limber on average. This is not like an established finding, but it's just possible. Maybe all dogs like lift their legs as high as they can. What if smaller dogs can achieve a greater angle on average. Another explanation could be going on here is over marking dogs like to write over another dog's female message. You know, they like to pee on top of it and be like,
I'm marking this now, and so they do that. And it could be that a smaller dog, by virtue of being smaller, has to really angle up to aim higher to over mark the mark left by a larger dog. Okay, so on average you'll get them trying to angle higher. But a third possible explanation is that this is basically animal behavior that is attempting to lie or be deceptive
about the dog's the author's right quote. Assuming body size is a proxy for competitive ability, small adult male dogs may place urinmarks higher relative to their own body size than larger adult male dogs to exaggerate their competitive ability. So like, I am huge, Look how high I can pee, while they're like bending over backwards basically to pee way up there as high as they can. So that's the idea about how dogs might be attempting to lie with their pe even if the p itself is honest, how
you pee isn't necessarily honest. But then again, I was kind of thinking about this, is this really a lie? I don't know. We'll come back to that in just a minute. But before we do, I wanted to mention one more thing. So there was a study in support of the lying or at least the body size exaggeration interpretation, and that was that the same dynamic has been observed in other mammals that use in environmental scent marking. A paper I was looking at here is called handstand scent
marking in the dwarf mongoose. This was in the journal Ethology in twenty twelve by Sharp, Juiced and Cherry, and the lead author here, Linda Sharp, is an ecologist at Australian National University in Canberra, and this study was looking at scent marking behaviors by the dwarf mongoose, which is known to use what is called handstand scent marking. To
quote the author's description here quote. In this flamboyant marking posture, the individual balances bipedally on its fore paws while flinging its hind legs up into the air and depositing its scent urine feces and or anogenital secretions one full body
length above the ground. So the animals that do this they literally stand up on their hands to reach us high up on like say the tree trunk or whatever it is, as they can to maybe rub their anal glands on it, or to rub whatever part of their body they need to, or to pee on it, to get up there as high as they can by fully inverting and going upside down.
Wow. Yeah, you see a behavior just like this in giant pandas. I don't know if this came up in the paper as well.
Oh, this wasn't about giant pandas, but I have read that pandas do this as well. Yeah, so anyway, the authors of this paper say that it was widely assumed that this type of marking is useful because it gives other mammals an idea of how big you are. You know when you do it, because you're flipping up your whole body length, and that's sort of like measuring your body essentially, so it's like you're leaving body measurements along
with your scent marking. But interestingly, the authors say quote, this study investigated the relationship between body size and handstand mark height in a wild population of dwarf mongooses in South Africa. We found that although body size and marking height were correlated positively, for female dwarf mongoose uses, they
were not for males. Male dwarf mongooses, who are subject to intersexual competition from outside their group, invested more heavily in anogenital range marking, marking at three times the female frequency and placing their deposits significantly higher than females, although they were not dimorphics I Meaning they're not actually bigger than the females. They're just like finding ways to get
the mark higher. Males that were particularly vulnerable to rivals i e. Those that were small for their age tended to mark higher than more robust age mates. And then they refer to a particular model of deceptive threat communication called the Atoms and Mesterson Gibbons model. But they say quote these findings suggest strongly that the height of anogenital
scent deposits is of social significance to dwarf mongooses. Now, on one hand, I was thinking, Okay, if this is true that in multiple mammal species, possibly including domestic dogs, there is in a tempt by smaller individuals to exaggerate their size by leaving their markings higher, should that be thought of as lying or should that actually just be
thought of as well. They're competing to place the mark as high as they can, and thus their ability to place the mark higher is signaling something like ability to place the mark. But I guess it's a question of like how widely that could or would be interpreted by other dogs as actually just reflecting them being bigger.
Hmm. Yeah, it's it's difficult to like really put ourselves once more in the mind of the animal. Like I guess it's it's kind of hard not to think about graffiti in comparison to this. And certainly if you see graffiti placed in a very hard to reach spot, you.
Know, oh, that's impressive.
Oh yeah, yeah, it can be quite impressive. We of course don't think, wow, that person was really tall. That person is like thirty feet tall to do that, but we might think that looks like a really dangerous and daring place to put a tag up.
Exactly right, Yes, we do think it's impressive, but not because we think they're giants. It's because of the imagining the feet that got them there.
But then again, with dogs, it's interesting, right with domestic dogs, you have such differing sizes in the species among the different breeds. Yeah, it kind of open like humans are only going to be so tall. But what if we did have a range of, say, you know, three to four feet to twenty to thirty feet, then perhaps we would have to consider these factors in looking at tags or many other things in life.
Yes, that's right. If cloud giants existed, you wouldn't necessarily assume somebody had like daringly climbed out.
Yeah, and for dogs, cloud giants kind of do exist. Yeah, they're just big breeds of dogs.
But this also makes me wonder could there be other ways? Since this is this one thing where it's possible, we don't know for sure, but it's possible dogs and other mammals are maybe trying to at least exaggerate their body size through these markings. You could maybe call this deceptive communication. What other kinds of things are we not even imagining that could be deception? Through chemical signals and stuff that we would normally think of as by definition almost honest signals.
I mean, could animals have kind of internal mechanisms for voluntarily regulating the presence of hormones or other things in their signals the same way that we can voluntarily control when we urinate.
Yeah, this is a fascinating question, Like I mean, one could imagine a scenario where a human could artificially ratchet up there, I don't know their stress response in order to create more stressful urine or the reverse. Like, to the extent that we can actually control these things, it seems possible that these levers could be in place to some degree or another in various organisms.
But then again, would that be kind of evolutionarily unstable, like if you you know, if you have enough dogs that are able to lie through their scent markings, with scent markings cease to be useful information. Yeah, I don't really know how the math of all that works out, but the.
Does that work out for humans? We see some olar problems with our ability to communicate. What happens when when truth erodes? What does that do to our trust in each other and in our ability to communicate?
Well, I'd say that's a hugely significant part of human life, Like a big part of what all culture is is just trying to separate truth from lies.
Perhaps you're in is better, that's what we're getting at all? Right, Well, I want to turn at this point to the world of the lobster, So not to be outdone, lobster not only pe on each other's faces. They pee out of their own faces to do this. That's great, and I
love this fact in and of itself. It kind of turns the very idea of urine upside down, and I think kind of humbles the human reader or listener, because I feel like, you know, your initial reaction to something like this might be something like, oh, well, that's weird and or funny that they do this with their urine.
But I think it's the fact settles in, it evolves into a different realization and you realize, truly, these creatures stand apart from us, and while they do not understand human complexity, ours is the greater deficiency because we clearly do not understand and have never understood the very nature of urine outside of our narrow human perspective.
Well said, I mean, I think that's shaping up to be the main takeaway of this whole series of it.
And I find this is also interesting because yeah, they're literally peeing out of their faces into other faces, and you could compare that on some level to the way words come out of our face, out of our head and then are interpreted by the censor ray on another into the individual's head. Yeah.
I mean, if you're just some kind of like alien metazoan coming in like studying human anatomy, you look at us, you're like, wait. They use one hole on their faces to mash up and swallow food. But then they also like flap things in that hole to make sounds at each other, which is how they share information. And then they can also sometimes attack one another with like teeth, with little sharp things in that hole and like bite. And they also use that hole in like mating rituals
with each other. And they also use that hole to breathe, to take it into oxygen and the vomit and to vomit. Yeah, from a sufficiently alien perspective, I think the single mouth hole issue is about as weird as the lobsters peeing in each other's faces. But the lobsters are no less weird for that.
Right now, I want to note that lobster here covers a lot of ground. Lobster tends to refer to various deck of pot odds with comparable body plans. Several papers I looked at concerned claude lobsters or true lobsters of the Nephropodias superfamily, but other papers I looked at, were looking at spiny lobsters or ling ghostas of the Pollinuridae family. I'm to understand that the power of urine is strong in both of these and that both in essence pee
through their faces. We also see this to some degree in crabs as well, but specifically dealing with lobsters, spiny or claude and peeing out of the face. I feel like we got to we got to sort of take this revelation in phases. First of all, how you're in from face, and we'll momentarily set aside whether this constitutes a face or front of head with the lobster. The lobster is not a creature that I look at and
I'm like, oh, look at look at its face. It's more just like it looks at the frontal array of sensory organs.
As lee we established in the past, I'm much more of a sucker when ruling things into the face category. I think if I see at least two eyes above the mouth parts, that's a face.
All right, Well, you know, fair enough. So with these lobsters, urine is excreted through the antennel glands. These are thought to be versions of the coxaile glands or maxillary glands. These are the excretory openings found in some arthropods and most erachnts. But while the glands are further down on other organisms, lobsters in their kin feature them much further up, essentially on the face if we're going to call it
a face, under the base of each antenna. Thus the name and the opening of the antennel gland is called the nephropore. Now the urine, which, as we'll discuss, is both excretory and communicative in purpose. I guess that's worth driving home is that like the dog, it's still excreting waste when it urinates, but it also has this.
Other why not both?
Yeah? Yeah, But with the lobsters, it's still emerging from bladders, and the bladders are adjacent to the creature's brain.
That's funny too, Like when your bladder's full, it's like you can feel it pressing on your brain. Just can't imagine that.
But I mean, look at us where our pie hole is right up here next to our brain as well, And yeah, you can make a case for that being weird. Uh huh. Now, let us consider why you're in from face and I think our number one answer should be, of course, why not? You know, does it matter? Sharks and some amphibians excrete liquid waste through their skin. Sharks also excrete through their gills. The Chinese soft shell turtle can apparently excrete you're in through the mouth, you know.
If anything, consider how much easier it would be if we in fact urinated through our faces instead of having to use our other parts.
Having trouble assessing whether that would be an upgrade or a downgrade.
I mean it would change a lot of things. Yeah, you could make a case that if would then mean well, then we'd wear pants on our heads as well, But maybe it would mean that you could you not use those other parts for urination and just set those aside for other purposes. Sure. On top of this, though, there are basically two main reasons that I was reading about for why have urine come out of your face or
the front of your head. First of all, as we've been getting at, urine is highly important for communication for the lobsters. We'll come back to how and it simply makes sense for all of this to be front loaded onto the head and adjacent to this because you might because I imagine you're instantly thinking, well, my dog doesn't pee out of its head and it p is important for it. Well, but your dog isn't a din dweller. That's the other argument made with the lobsters is that they'll spend a
large portion of their life in little dens. Communicating to others to come into your den or to stay away from your den is important, and it makes sense to front load your urine excretion systems in order to broadcast outside of the den, you know, outside of the rocks, outside of the corals, wherever you happen to be held up at a given moment.
That makes sense, okay, Yeah.
And they can apparently excrete the you know, sometimes it's hard for us to imagine, like what is it like to like squirt urine underwater? And I think we'll probably get into more of this in a subsequent episode. We can get into fish, but with the lobster, apparently they can really push the urine out like multiple multiple body lengths all right. Now, the next level is to consider what is communicated through the urine pheromones and other chemical
signatures that feature intomate selection and competition. These are apparently some of the big ones and the ones that have been studied the most. Females will use their urine to indicate that they are ready to mate, and following competition between males, the winner of those competitions will then broadcast
their serotonin rich urine to declare their victory. I was thinking about this when we were talking about lying and urine, like, I think this would be a case where it would be impossible or unlikely that you would be able to lie, because the contents all the year are kind of like signaling your victory. Like there, it's an seemingly authentic chemical signature of the way you feel after defeating another lobster
or scaring off intimidating another lobster. On top of this, the female you're in apparently is thought to calm the male and will also keep other females away and say like, Okay, this den is now claimed, I am shacking up with this male lobster. Go your own ways. I was reading a bit about this in a Snoop's article actually by Madison Dapkovich, and two other sources that I looked at were Chemical Communication and Crustaceans Lobsters from twenty ten by
Aggio and Derby. And a novel tegmental gland in the nephropoor of the lobster Homarus americanas by Bushman and Attema from nineteen ninety three, this latter being I think a
commonly cited source over the years. Now, I want to add that lobster reproduction is pretty fascinating in and of itself, you know, talking about like the males and female talking to each other, the males competing well, the male and the female apparently form quite a bond, and then the female molts, sheds her exoskeleton in order to mate with the male. Now, as with pretty much any exoskeleton equipped organism,
molting is part of your continual development process. You're always growing out of and then growing new armor, and you'll see this in the lobsters, of course, but it's essential here for the reproduction. The female has to shed the exoskeleton in order to reproduce, and during this time she's vulnerable,
but she's also protected by the male. The eggs that result, up to like one hundred thousand of these will then remain attached to her swimmerettes under her tail for nine to twelve months, and of course she eats, she builds up her strength and gets that exoskeleton back as she recovers, You've.
Never seen a lobster with all the eggs under the tail is pretty cool looking. It's where they've got sometimes it's called caviare I guess looks kind of like that. It's like a million little balls. They're curled up on the underside of the body.
Yeah, they're fascinating and we're only just dipping our toes really into the lobster waters. They're the fascinating organisms now. I also looked at a couple of articles dealing specifically
with the urine of the spiny lobster. A two thousand and nine study from Shabini at All published in the Journal of Experimental Biology, points out that urine factors into aggressive behaviors between male spiny lobsters, and along with physical aggression, the urine helps to broadcast social status and reduces overall
physical aggressive behaviors. So they cited some experiments that involved like removing the ability from a studied lobster to urinate and actually like spread it's into this necessary information and then what happens when you then pump that urine into a given conflict zone for spiny lobsters, And basically this is a great example of what we were talking about earlier, like the more urine, like urine gives information, it broadcasts information,
and the more information that is out there, the less absolute violence has to occur between these competing males piece through p Yeah exactly, yeah yeah. On top of this, spiny lobsters may apparently sometimes seek each other out to sort of like aggregate and shelter, and they'll find each
other via their urine. And finally, another interesting finding that I came across this is coverage in The Guardian authored by Richard Luscom from twenty twenty four pointing out that the urine of the spiny lobster can also serve as a kind of accidental warning to various prey species that the spiny lobsters of course feast on in their coral reef habitats, and the smell of this urine can actually scare off various organisms that feast on vulnerable and degraded coral,
offering them some amount of protection. And this can be especially be helpful in cases where you have nursery grown coral restoration projects. So like this nub of nursery grown coral that you're trying to like establish and re establish in a given area. You know, it's a highly delectable meal to these organisms such as the coral, liverous snails, and fireworms. So the presence of the spiny lobster urine can actually like drive them away and keep them away.
And it's just I guess part of this just comes back like, as far as I could tell, there's not actually like anybody's saying, well, we need to pump spiny lobster urine into an area. It's more like, well, you need a balanced ecosystem, and spiny lobsters are part of that balanced ecosystem, and so their presence can help protect these vulnerable corals.
So, from the lobster's evolutionary perspective, the urine is sending both intended and unintended messages. It's both the communication that you're, the conversation you're having with somebody at the table with you, and also the person eavesdropping on you from next door.
Yeah. Yeah, it's like between lobsters of the same species, urine is language, and it's it's negotiating these various scenarios. And then in the case of these coral eating creatures and the spiny lobster. It's like essentially like hearing the howl of the spiny lobster a terrifying announcement that predators are near. And yeah, spiny lobsters eat a lot of a lot of critters in their choral environments. Like they're
they're they're important predators. It's easy to focus on something like this as food since it is on the menu for human beings, but yeah, they eat a lot of critters, including these critters that are dangerous to to to endangered corals.
Well, I found this section about lobster face peas strangely heartwarming.
Yeah. Yeah, they're they're complex organisms. It's it, you know, the lobster. You know, it really kind of goes back to to David Foster Wallace is considered the lobster from two thousand and four. There's, you know, we often just take them for granted because we just think of them as food and really only you know, to the content of his article only recently as kind of like upper
class food. And it's easy to assume that they're just simple creatures that do not have these complex interactions, but that they do. Yeah, they're fascinating.
All right, Well, do we want to wrap up part two there and come back next time for more about urine based communication?
Sounds like a plan in the meantime. Yeah, we'd love to hear from everyone out there if you have thoughts on either of these two episodes regarding urine. I'm sure you dog owners have some tales to share with us. Ride in certainly, and maybe we'll feature those on an upcoming listener mail episode. A reminder that Stuff to Blow Your Mind is primarily a science and culture podcast, with
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